Warning! complete Linux ignoramus...
I think I need some help here! The Humax HDD test stalled - it said it would take a few minutes, but you're saying several hours - perhaps I was not sufficiently patient. I tried a reformat and, as has happened before, the Humax refused because the disk is too large (it's 1TB). I then tried the manual format steps in your 2TB disk preparation blog, i.e.
humax# mkfs.ext3 -m 0 -O sparse_super /dev/sda1
humax# mkfs.ext3 -m 0 -O sparse_super -T largefile /dev/sda2
humax# mkfs.ext3 -m 0 -O sparse_super /dev/sda3
The first command worked, the second failed because the partition was mounted. I could experiment with umount and fdisk, but I don't really know what I'm doing, so some help would be appreciated. I assume I have to delete the existing partitions before I can recreate them. At the moment I can still see the exiting recordings on the disk (all of which are backed up), but I cannot record or pause viewing, presumably due to my having borked sda1.
Given the present confused state of the disk, could you please talk me through all the steps needed to perform a full manual reformat? If I just use fdisk to delete the 3 existing partitions, will the Humax format the disk automatically after a reboot, or do I also need to create the partitions as above?